Electric switch



G. A. BURNHAM ELECTRIC SWITCH Filed June 5, 1920 2 Sheets-Shaw.A 1

0 m w 3, 8 m 4, c.. 2 .1L .M JZ/0 #v 0 m z 22 Z /MH 2 M o i H K AWM Y; Wm. Rss Uw e R n wm G m Feb. 12 1924.

j?? U62? ivf,

CLM

Patented Feb. 12, 1924.

UNITED STATES GEORGE A. BURNHAM, 0F SAUGUS, MASSACHUSETTS, ASSIGNOR T0 SEARS B. CONDIT,

PATENT OFFICE.

OF BROOKLINE, MASSACHUSETTS.

v ELECTRIC SWITCH.

Application filed June 3,

fo ZZ fio/icm t may concern Be it known that I, GEORGE A. BURNHAM, a citizen of the United States, residing at Saugus, in the county of Essex and State of Massachusetts, have invented an Improvement in Electric Switches. of which the following is a specification.

This invention relatesto an oil immersed electric switch adapted to control and interrupt circuits carrying relatively high values of current and is of ythe type disclosed in my co-pending applications Serial No. 309,853, filed July 10, 1919; Serial No. 374,276, filed April 1G, 1920; and Serial No. 381,466, sied May 14., 1920.

In said applications I hare set forth an electric switch having a resiliently supported oil receptacle and a switch frame forming a cover forvsaid receptacle having a peripheral flange or apron depending downwardly over the side wall of the receptacle and closely spaced therefrom to provide a narrow passage, although of comparatively great total area, down which vaporized liquid and gases will pass into a spill receptacle.

The object of this invention is to provide a switch of the above type with a plurality of gas channels formed byproviding a plurality of projections, as ribs, or the equivalent on the inner face of said apron with relatively large passages therebetween adapted to engage and support the wall of the movably mounted oil ,receptacle when pressure is generated within the switch, as upon circuit interruption and the side-walls of thev receptacle are forced outwardly; over which the oil receptacle is adapted to move as it yields downwardly due to the pressure. The total surface of the ribs in engagement with the side-walls of the receptacle is adapted to be relatively small so that but little frictional resistance will be offered to oppose movement of the receptacle, even with a considerable pressure acting to force the side-wall againstthe ribsrand the spacing of the ribs is adapted to be vsuchthat ample area is provided therebetween for the expulsion of liquid and vapor, yetl the ribs or other projections are adapted to be sufficiently closely spaced to 'support the side wall and prevent it from being forced into and close the passages.

Fig. 1 is a side elevation, partly in sec- 1920. Serial No. 386,347.

tion, of a switch incorporating my invention.

Fig. 2 is a plan sectional detail along line r2--2 of Fig. 1'.

Fig. 3 is a sectional elevation of the switch of Fig. 1.

Fig. 4 is a sectional detail illustrating the relative position of the oil receptacle, and switch frame in a depressed position of the oil receptacle.

As here shown, the switch embodying my invention includes the switch frame 10 havthe extenderL arm 11 by which the switch is fixed to a support. Stationary and movable switch members 12 and 13 are carried by said switch frame and depend t-lierebelow and switch operating mechanism 14 is also carried by said frame.

The switch frame is formed with the peripheral depending flange or apron 15 which is adapted to enclose the oil recep- Vtacle 1:6 and depend a considerable distance down the side wall thereof whereby downwardly to guide oil and vapor expelled from the switch upon circuit interruption.

Said oil receptacle 16 is received within and supported by an outer receptacle or spill tank 17, the side-'walls of which are relatively closely peripherally spaced from the side-walls of the oil receptacle whereby to provide a relatively narrow and long chamber adapted to receive the oil and vapor expelled from the switch and condense the condensa-ble vapor and collect and retain it and the oil. The side-walls of said spill receptacle preferably extend upwardly beyond the lower end of said apron 15 whereby practically all of the oil and vapor will be directed into the receptacle; and the sidewalls are relatively closely :spaced from said apron whereby to provide a relatively narrow passage which, while of ample area freelyk to permit the discharge ofV uncondensed vapor and gas Vfrom the receptacle, will, in combination with the shape of the chamber between the two receptacles, prevent the maintenance of combustion therein.

Said outer receptacle rests upon the grids 18, or it may be one grid, whichextend laterally beyond the side walls of therec'eptacle; and the extended end-portions are provided with apertures. Rods-19 are 'received iny said apertures and are fixed to said grids. Said rods extend upwardly on opposite sides of the outer receptacle and through apertures in extended lugs 2O of the switch frame. The upper end-portions ot said apertures are enlarged to form the spring-receiving recesses Q1 and compression springs 22 are received in said recesses and encircle said rods. The upper end-portions are threaded and nuts 23 are removably threaded thereon and engage the upper end of said springs whereby a yielding support for the oil receptacle is provided. The oil receptacles may be removed from the switch frame by removing said nuts.

Ordinarily said springs are adapted ,'ieldingly to hold the top of the oil receptacle 16 directly in Contact with the under side of the switch frame and yield, under influence of pressure within the switch, to permit the receptacle to move away from the switch trame whereby to provide a relatively large opening for the expulsion of oil and gas or vapor. Normally the switch will be what is termed non-vented yet, due to irregularities of contact between the top ot the oil receptacle and the switch trame, suiiicient clearance space will be formed therebetween to enable the switch to breathe.

For some purposes, however, it may he desirable to provide a definite passage ot substantial height between the top of the receptacle and the switch Jframe so that the switch will be at all times in substantially unrestricted communication with the atmosphere, or freely vented. This result may be accomplished by limiting the extent ot' upward movement of the oil receptacle under influence of said springs by suitable means, as by the sleeves 24 tixed to said rods 19 beneath said lugs 2O and so disposed thereon as to engage the bottom of said lugs and limit further upward movement ot the receptacle.

Oil and gas and vapor expelled from the switch as during circuit interruption and when the oil receptacle moves downwardly is adapted to pass over the top of the oil receptacle and downward between the sidewalls of said receptacle and said apron 15 into the outer or spill receptacle.

Considerable Jressure may be set up within the switc upon certain conditions oit circuit interruption, and the pressure may be suticient to distort the oil receptacle and torce its side-walls against said apron 15 suiiiciently strongly to prevent the proper' yielding or downward movement of the receptacle; and also may materially reduce the eective area of the vent passage between the receptacle and apron. For this reason means are provided whereby the extent of contact between the side-walls and the apron will be small and the walls of the receptacle will be supported by the apron at numerous points. Said means specifically comprises the plurality of vertically disposed rihs integrally formed on the inner lace et said apron 15, and extended therebeyond adapted to engage and support the side wall oit the oil receptacle 1G. Said ribs preterahly extend vertically the length ot the apron whereby the greatest support 'tor the walls of the oil receptacle is provider The width of said ribs is relatively small whereby but small surface is presented to oppose movement of the oil receptacle. A rc ively large number of ribs are provided wnerelw the receptacle will be supported at numerous points; and the spaces a between the ribs provide passages tor gas and oil lf-nipelled from the switch, the total area oi" wh ch is relatively large. r1`he spacing ci the ribs is sufficiently close to support the walls et the oil receptacle against appreciable bulging into the spaces a.

I claim:

1. An electric switch comprising a switch frame and an oil receptacle movahly supported relative to said trame; said 'trame having a peripheral apron depending therefrom surrounding and peripherally spaced from the upper portion of said oil receptacle and having a plurality ot supporting projections extended from its inner 'tace to engage and support the side walls ot said oil receptacle and provide a vent passage hetween said receptacle and frame in moved positions of the oil receptacle.

2. An electric switch comprising a switch frame and an oil receptacle movahly supported relative to said frame, said trame having a peripheral apron depending therefrom surrounding and peripherelly spaced from the upper portion of said oil receptacle having a plurality ot vertically-extended channels in its inner tace to provide vent passages between the side walls et said receptacle and said apron.

3. An electric switch comprising a switch frame and an oil receptacle nnwably supported relative to said trame, said 'trame having a peripheral apron depending therefrom surrounding and peripherally spaced from the upper portion of said oil receptacle having a plurality ot supporting' projections of relatively small snntsce area extended from its inner tace to engage and support the side walls ot' said oil receptacle and provide and maintain a vent paf-:sage between the side walls ot said reeeptarle and said apron in moved positions et said rv,- ceptacle.

In testimony whereof, 1 have signed my name to this specification.

GEORGE A. BURNHAM. 

